package com.chianghao.core.utils;

import java.io.IOException;
import java.security.SecureRandom;
import java.util.Base64;

import javax.crypto.Cipher;
import javax.crypto.SecretKey;
import javax.crypto.SecretKeyFactory;
import javax.crypto.spec.DESKeySpec;

import com.chianghao.core.exception.HaoException;


/**
 * DES加密 解密算法
 * 
 * @author chianghao
 * @date 2015-3-17 上午10:12:11
 */
public class DesUtils{

	private final static String DES = "DES";
	private final static String ENCODE = "UTF-8";
	//private final static String defaultKey = "ABCDEFGH";

	/**
	 * 使用 默认key 加密
	 * 
	 * @return String
	 * @author chianghao
	 * @date 2015-3-17 下午02:46:43
	 */
//	private static String encrypt(String data) throws Exception {
//		byte[] bt = encrypt(data.getBytes(ENCODE), defaultKey.getBytes(ENCODE));
//		String strs = Base64.getEncoder().encodeToString(bt);//.encode(bt);
//		return strs;
//	}

	/**
	 * 使用 默认key 解密
	 * 
	 * @return String
	 * @author chianghao
	 * @date 2015-3-17 下午02:49:52
	 */
//	private static String decrypt(String data) throws IOException, Exception {
//		if (data == null)
//			return null;
//		//byte[] buf = decoder.decodeBuffer(data);
//		byte[] buf = Base64.getDecoder().decode(data);//decoder.decodeBuffer(data);
//		byte[] bt = decrypt(buf, defaultKey.getBytes(ENCODE));
//		return new String(bt, ENCODE);
//	}

	/**
	 * Description 根据键值进行加密
	 * 
	 * @param data
	 * @param key  加密键byte数组
	 * @return
	 * @throws Exception
	 */
	public static String encrypt(String data, String key)  {
		try {
			byte[] bt = encrypt(data.getBytes(ENCODE), key.getBytes(ENCODE));
			String strs =  Base64.getEncoder().encodeToString(bt);
			return strs;
		}catch(Exception e) {
			throw new HaoException("string to byte[] is error"+e.getMessage());
		}
		
	}

	/**
	 * Description 根据键值进行解密
	 * 
	 * @param data
	 * @param key  加密键byte数组
	 * @return
	 * @throws IOException
	 * @throws Exception
	 */
	public static String decrypt(String data, String key) {
		if (data == null)
			return null;
//		BASE64Decoder decoder = new BASE64Decoder();
		byte[] buf =  Base64.getDecoder().decode(data);
//		byte[] buf = decoder.decodeBuffer(data);
		try {
			byte[] bt = decrypt(buf, key.getBytes(ENCODE));
			return new String(bt, ENCODE);
		}catch(Exception e) {
			throw new HaoException("string to byte[] is error"+e.getMessage());
		}
	}

	/**
	 * Description 根据键值进行加密
	 * 
	 * @param data
	 * @param key  加密键byte数组
	 * @return
	 * @throws Exception
	 */
	private static byte[] encrypt(byte[] data, byte[] key)  {
		try {
			// 生成一个可信任的随机数源
			SecureRandom sr = new SecureRandom();
			// 从原始密钥数据创建DESKeySpec对象
			DESKeySpec dks = new DESKeySpec(key);
			// 创建一个密钥工厂，然后用它把DESKeySpec转换成SecretKey对象
			SecretKeyFactory keyFactory = SecretKeyFactory.getInstance(DES);
			SecretKey securekey = keyFactory.generateSecret(dks);
			// Cipher对象实际完成加密操作
			Cipher cipher = Cipher.getInstance(DES);
			// 用密钥初始化Cipher对象
			cipher.init(Cipher.ENCRYPT_MODE, securekey, sr);
			return cipher.doFinal(data);
		}catch(Exception e) {
			throw new HaoException("des encrypt error =>"+e.getMessage());
		}
	}

	/**
	 * Description 根据键值进行解密
	 * 
	 * @param data
	 * @param key  加密键byte数组
	 * @return
	 * @throws Exception
	 */
	private static byte[] decrypt(byte[] data, byte[] key)  {
		// 生成一个可信任的随机数源
		try {
			SecureRandom sr = new SecureRandom();
			// 从原始密钥数据创建DESKeySpec对象
			DESKeySpec dks = new DESKeySpec(key);
			// 创建一个密钥工厂，然后用它把DESKeySpec转换成SecretKey对象
			SecretKeyFactory keyFactory = SecretKeyFactory.getInstance(DES);
			SecretKey securekey = keyFactory.generateSecret(dks);
			// Cipher对象实际完成解密操作
			Cipher cipher = Cipher.getInstance(DES);
			// 用密钥初始化Cipher对象
			cipher.init(Cipher.DECRYPT_MODE, securekey, sr);
			return cipher.doFinal(data);
		}catch(Exception e) {
			throw new HaoException("des decrypt error =>"+e.getMessage());
		}
		
	}
}